Update hypothesis requirement from <=6.98.6 to <=6.98.8 (#1934)

Updates the requirements on [hypothesis](https://github.com/HypothesisWorks/hypothesis) to permit the latest version.
- [Release notes](https://github.com/HypothesisWorks/hypothesis/releases)
- [Commits](HypothesisWorks/hypothesis@hypothesis-ruby-0.0.1...hypothesis-python-6.98.8)

---
updated-dependencies:
- dependency-name: hypothesis
  dependency-type: direct:production
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements/test.txt

@@ -1,4 +1,4 @@
-hypothesis<=6.98.6
+hypothesis<=6.98.8
 Pyro4
 pytest-freezer
 pytest-sugar==1.0.0